ISiO. 2.] EDWARDS — MONTREAL WATER SUPPLY. 121 



It will seen from this table of analyses that the Montreal 

 water suppl}^ is a most valuable product, and that it often con- 

 tains excess of mineral matter in suspension, and sometimes organic 

 debris from local or temporary causes. A far more wholesome 

 water supply would be secured from the same source by the 

 addition of settling beds of masonry and filter beds of gravel 

 and sand after the Liverpool model, which I am informed should 

 not cost more than 10 cts. per 1000 gallons, and would certainly 

 contribute hirgely to the health of the inhabitants and to the 

 hygienic reputation of the city. Moreover, upon other economic 

 grounds, this is a wise and prudent improvement, which h:is been 

 too long denied to the well-taxed public of Montreal . This I 

 have urged to the successive Mayors, Chairmen of Boards of 

 Health, and of the Water Committees, and I wish once more to 

 urge these considerations on the municipal and sanitary autho- 

 rities. 



The waters of the Ottawa and of the north district generally 

 which flow past Montreal island are remarkable for the sandy or 

 flinty character of their minute animal and vegetable organisms, 

 and for the presence of alkaline silicates, which when co-mingled 

 with the waters of the St. Lawrence become precipitated into 

 gelatinous hydrate of silica. xVs the result of frequent micros- 

 copic examinations of the deposits formed by subsidence of the 

 water supplied to my laboratory, and also the deposits separated 

 by the process of filtration in my house filter, I find that the 

 deposits consist of 



1. Angular fragments of sand and jiint. 



2. Gdatinous silicious magma. 



3. Organic sUicious filaments of Diatoms^ also sjjicides and 

 gemmides of fxsh-water Sponges iind skeletons of Algce. This 

 deposit resembles in general character the well-known '• Tripoli 

 powder " used for the burnishing of metals, the keenness and 

 polishing power of which, is due to the presence of similar veg- 

 etable sandy fragments, which are scarcely less hard than 

 " Emery powder " and will cut fine scores in the brass work of 

 taps and valves, which, followed by hard particles of sand, give 

 rise to continual leakage. 



Therefore, I submit that the filtration of the water, before it 

 is pumjyed into the mains of the city, would, by removal of this 

 gritty fiinty matter accomplish a saving o/* u-cfs^e alike in water, 

 taps, valves and working machinery, which would more than repay 



